Prime number checker and factorization tool
The building blocks of all numbers
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. The first primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29... 2 is the only even prime: Every other even number is divisible by 2, making it composite. This makes 2 unique among primes. How to check if a number is prime: Only check divisibility by primes up to the square root. To test 97: check 2, 3, 5, 7 (√97 ≈ 9.8). If none divide evenly, it's prime. Infinitely many primes: Euclid proved around 300 BCE that there are infinitely many prime numbers. The largest known prime (as of 2024) has over 40 million digits. Why primes matter: RSA encryption (securing online banking, email, HTTPS) relies on the fact that multiplying two large primes is easy, but factoring the result back into its prime components is computationally infeasible.
About prime numbers
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. Examples: 2, 3, 5, 7, 11, 13...
Other useful tools related to mathematical calculations
How to Use? Enter the number you want to check. Shows if the number is prime and lists all its factors.
Quickly check if a number is prime
Lists all factors (divisors) of the number
Breaks number down into prime factors
Optimized algorithm for quick results
About prime numbers
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. Examples: 2, 3, 5, 7, 11, 13...